1. Field of the Invention
The invention relates generally to wireless communications. In particular, the invention relates to fairness provision via controlling a transmission opportunity window in a wireless mesh network.
2. Description of the Related Art
Various wireless mesh network technologies have recently emerged providing dynamic and cost effective connectivity over a given geographic area. A wireless mesh network is a communications network consisting of radio nodes organized in a mesh topology. Wireless mesh networks often consist of mesh clients, mesh routers and gateways. The mesh clients may be e.g., laptops, cell phones, and other wireless devices while the mesh routers forward traffic to and from the gateways which may, but need not, connect to the Internet. A mesh network is reliable and offers redundancy. If one node can no longer operate, the rest of the nodes can still communicate with each other, directly or through one or more intermediate nodes.
One of the wireless mesh network technologies is IEEE 802.11s which is an extension to IEEE 802.11 set of standards for implementing a wireless local area network (WLAN). Another wireless mesh network technology involves ad hoc device-to-device (D2D) communication in cellular networks but without cellular coverage.
A transmission opportunity (TROP) window may be used in wireless mesh networks as a basic unit of allocation of the right to transmit onto the wireless medium, i.e., a transmission opportunity window is the interval of time when a station has the right to initiate its transmission. During a single transmission opportunity window, a station can trans-mit several frames without any contentions with other stations or without any additional polling from an access point (AP). The transmission opportunity window allows a station to transmit a multitude of frames one after another, as long as all the frame transmissions occur within the duration of the current transmission opportunity window.
However, there is a serious disadvantage in current implementations of the transmission opportunity in that, while the transmission opportunity window can be different depending on the traffic class of the corresponding packets, within frames of the same class the transmission opportunity window is identical, regardless of data transmission rate capabilities of the respective station. That is, the current implementations of the transmission opportunity provide fairness with respect to the time each stations accesses the wireless medium but not with respect to data rate that each station communicates.
Therefore, an object of the present invention is to alleviate the problems described above and to introduce a solution that allows fairness provision in wireless mesh networks with respect to the data rate that stations communicate.